Accepted for Publication: October 16, 2012.
Published Online: March 18, 2013. doi:10.1001/jamainternmed.2013.2352
Author Contributions:Study concept and design: White and Murin. Acquisition of data: White. Analysis and interpretation of data: White, Geraghty, Brunson, Murin, Wun, Spencer, and Romano. Drafting of the manuscript: White. Critical revision of the manuscript for important intellectual content: White, Geraghty, Brunson, Murin, Wun, Spencer, and Romano. Statistical analysis: Geraghty, Brunson, and Romano. Administrative, technical, and material support: Wun. Study supervision: White and Wun.
Conflict of Interest Disclosures: None reported.
Funding/Support: This study was supported by the Hibbard E. Williams Endowment at the University of California, Davis (Dr White).
Previous Presentations: This study was presented at the Thrombosis and Hemostasis Summit of North America 2012; May 4, 2012; Chicago, Illinois.
Additional Contributions: Debra F. Gonzalez, GISP, assisted with the geographic mapping, and Zhongmin Li, PhD, provided statistical expertise.